1. Field of the Invention
Exemplary embodiments of the invention relate to a stereoscopic image display and a method for driving the same.
2. Discussion of the Related Art
A stereoscopic image display is classified into a display using a stereoscopic technique and a display using an autostereoscopic technique. The stereoscopic technique, which uses a parallax image between left and right eyes of a user with a high stereoscopic effect, includes a glasses type method and a non-glasses type method, both of which have been put to practical use. In the glasses type method, the parallax image between the left and right eyes is displayed on a direct-view display or a projector through a change in a polarization direction of the parallax image or in a time-division manner, and thus a stereoscopic image is implemented using polarization glasses or shutter glasses. In the non-glasses type method, an optical axis of the parallax image between the left and right eyes is separated using an optical plate such as a parallax barrier and a lenticular lens, and thus the stereoscopic image is implemented.
FIG. 1 schematically illustrates a shutter glasses type stereoscopic image display. In FIG. 1, a black region of shutter glasses ST represents a shutter that blocks light traveling toward an observer (i.e., viewer), and a white region of the shutter glasses ST represents a shutter allowing transmission of light toward the observer. When a liquid crystal display element is selected as a display element DIS, a backlight unit providing light to the display element DIS is necessary.
As shown in FIG. 1, during odd-numbered frame periods, left eye image data RGBL is written to the display element DIS, and a left eye shutter STL of the shutter glasses ST is opened. During even-numbered frame periods, right eye image data RGBR is written to the display element DIS, and a right eye shutter STR of the shutter glasses ST is opened. Thus, the observer can view only a left eye image during the odd-numbered frame periods and can view only a right eye image during the even-numbered periods, thereby obtaining a stereoscopic feeling.
A method illustrated in FIG. 2 of U.S. Pat. No. 7,724,211 is known as method for driving the shutter glasses type stereoscopic image display. As shown in FIG. 2, the method includes at least two frame periods, for example such as a (2N−1)th frame period and (2N)th frame period in order to display the stereoscopic image, wherein N is a natural number. The (2N−1)th frame period includes a data addressing period in which data of a single eye image (i.e., a left or right eye image) is addressed, and a vertical blanking interval VBI. The 2Nth frame period includes a data addressing period in which data of another single eye image (i.e., the right or left eye image) is addressed and a vertical blanking interval VBI. In the method illustrated in FIG. 2, if left eye image data is addressed during the data addressing period of the (2N−1)th frame period, the left eye shutter may be opened during the vertical blanking interval VBI of the (2N−1)th frame period. If right eye image data is addressed during the data addressing period of the 2Nth frame period, the right eye shutter may be opened during the vertical blanking interval VBI of the 2Nth frame period.
However, in the method illustrated in FIG. 2, when a stereoscopic image is displayed, the shutter glasses is driven during only the vertical blanking intervals VBIs which are relatively shorter than the data addressing period. Hence, a luminance of a three-dimensional (3D) mode is reduced to approximately 1/10 of a luminance of a two-dimensional (2D) mode because of a rising response delay TR of liquid crystals of the shutter glasses. Further, 3D crosstalk may be generated because of a falling response delay TF of the liquid crystals of the shutter glasses. The 3D crosstalk means an incomplete isolation of the left and right images so that one leaks or bleeds into the other.